Discussion forum for UAVDevBoard, Sparkfun's 3-axis IMU-based autopilot board

This is the place to discuss the new open source IMU-based autopilot board by Bill Premerlani.

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Thanks Bill,

                 Ordered and delivered. HMC5843 3-axis magnetometer arrived.  I'll be working on it shortly.

Will there be a USB connector on the upcoming Version 4 board?  And do you have a link to the discussion area? I'll also be getting airspeed and pressure/temperature boards for this soon.  Current platform 98" wing span MQ-9 Predator. Flight results will be logged and I hope to make that available here. 


Greatly appreciate all the work you and your team does - A Mighty Thanks,

John Galczynski


Hi John,
The UDB4 will have lots of spare pins, but no USB connector.
Here is the URL of the UDB discussion group:


Here is the URL of the UDB web page:


Best regards,

Hi Bill, just want to ask you, if the UAVdev board can send/receive data from Ground station Planner - Michael Oborne or even from happyKilmore´s ground station ?


 thanks in advance.

Hi Gil,

Both the ArduStation and HappyKilmore's ground station will display data sent from the UDB to the ground station.

We plan to eventually support Mavlink in both directions when the UDB4 goes into production in a couple of months.

Best regards,


Hi All,


I need some help, I want to know if there is a way to see the coding structure flow diagram or some information as to how the code was set up. I want to attach a pressure sensor to the UAV V3 because I want to improve the accuracy of the altitude readings because we are flying closer to the ground possibly less then 60m. The problem is I dont know how or what to change to use the pressure sensor reading for the altitude measurements rather than the GPS. Is this a big job and would it possible with the new code and UDB 3?


Thank you!

I think I messed up. My new UAV DevBoard arrived today. I didn't read deep enough into the instruction site before buying the GPS, and I ordered the D2523T from Sparkfun, thinking it was OK because it also used the u-Blox 5 engine. Then I saw that it wasn't supported, but the u-Blox 407 is. Unfortunately, everyone seems to be out of the u-Blox 407, and some of the comments I've read about the EM-406 say it has a slow response time. Does the D2523T absolutely not work with the DevBoard? If not, I'll have to get an RMA and send the D2523T back. And if I have to do that, which would be a better replacement, EM-406 or Mediatek?


@Tony, EM406A is the tried and tested GPS solution with uav devboard. It is the founder's (Bill Premerlani's) favourite. You don't need fast GPS with uavdevboard, as it works out where it is 40 times / second with the accelerometers and gyros. You just need an accurate position every second or so, and that is what matters. Even the delay (about 1.25 seconds) of the position does not matter, as the firmware takes that into account when updating the error in positioning by the accelerometers and gyros (integrations).

The MediaTek is still a very newly supported device for th UAV DevBoard. A lot of people reported problems, although they may have been running theUDB with the wrong clock rate. I recommend you search the uav devboard discussionlist. Best wishes, Pete

Thanks for the info, Pete. Wish I had read just a little further before ordering. :(



OK, I corrected my error, and ordered a 406A. On the gentleNav page, under "Optional Equipment", OpenLog is recommended as a data logger. Would there be any advantage to having the hard-wired OpenLog data recorder over using a stand-alone recorder? I already have a Canmore GPS logger that I use on my planes at times.





Yes, it is advantageous to connect the OpenLog data recorder.


The openlog will store the telemetry as it is emitted from the uavdevboard. The preferred format at the moment is SERIAL_UDB_EXTRA, and provides much more information than just the GPS data from the plane. You can see a copy of the telemetry format here.  The additional information stored is:-

  • The IMU position as opposed to the GPS positions (GPS is always delayed by at least 1.25 seconds)
  • The orientation of the plane by keeping the elements of theDirection Cosine Matrix (Yaw, roll and pitch can be derived from DCM.)
  • The estimated wind vector throughout the flight
  • The calculation of magnetic north (if you use a magnetometer)
  • The PWM pulses for all inputs and outputs (to the servos) throughout the flight
  • The status of the plane throughout the flight (Manual, Stabilized, Autonomous, Return to Landing)
  • The next waypoint that the plane is trying to reach.

All of the above can be processed by the python script call flight analyzer. That will conver the data into a form that can be viewed either in a spreadsheet or in Google Earth.


The Google Earth representation puts the data into a time animated form, and colour codes all the waypoints as well as providing layers which allow the user to switch on:-

  • display of model aircraft showing the orientation of the plane during the flight
  • overlay wind vectors
  • overlay magnetometer vector for magnetic North
  • Display the waypoints in 3D space along side the actual track of the aircraft. This is useful for determining how well your plane has actually flown the intended route.

Best wishes, Pete


Thanks for that info, Pete. That kind of data will be very useful in my project.



Doing a bit of reading in the UDB instructions last night. After installing the Pic drivers, it said to power up UDB before plugging the programmer into UDB. I thought I had read somewhere that UDB can get its power from the PicKit USB connection. I'm still searching the forums and wiki, but Is there a preferred method?


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